Well-known wireless power supply technologies include power supplies based on electromagnetic induction and power supplies based on radio waves. On the other hand, recently, power supplies based on magnetic resonance have been proposed.
In a wireless power supply system based on magnetic resonance, for example, resonant coils having certain resonant frequencies are arranged in a power transmitting device, and resonant coils having the same resonant frequencies as those of the power transmitting device are arranged in a power receiving device. A coupling of a magnetic field which realizes an electromagnetic energy transfer by the magnetic resonance is formed between the power transmitting device and the power receiving device, and the power is efficiently transmitted wirelessly from the resonant coils of the power transmitting device to the resonant coils of the power receiving device by the coupling of a magnetic field.
It is considered that, compared with a power supply system based on radio waves, a power supply system based on magnetic resonance is capable of supplying a larger amount of power, elongating a power transmission distance, and reducing a size of the coil for power transmission.
A certain well-known non-contact power supply device embodies a power supply stand which includes a first coil, a power supply, power supply controlling equipment, and a supply commanding unit, and which is installed on the ground. A second coil, a charge controlling circuit, and a battery are loaded on a vehicle. In charging the battery, the vehicle is made to stop in such a way that the second coil is located immediately above the first coil, a controlling signal is output to the power supply from the power supply controlling equipment by an operation of the supply commanding unit, and an alternating excitation current is supplied to the first coil from the power supply, which generates an induced magnetic flux. An alternating induced electromotive force induced in the second coil by this induced magnetic flux is converted into a direct current by the charge controlling circuit, the obtained direct current is supplied to the battery, and the battery is thereby charged. A control displaying unit calculates and displays the supplied power amounts and charges or wirelessly transmits them.
In a certain well-known power supply system, an ECU (electronic control unit) of the vehicle which transmits power executes a program which includes a step of wirelessly transmitting power to the vehicle which receives power. The ECU of the vehicle which receives power, when it receives power transmitted from the vehicle which transmits power, supplies the received power to a driving motor, and executes a program which includes a step of driving a driving motor. With this, when the vehicle is traveling, power transmission and reception are available. The power supply system calculates fees on the basis of the transmitted power and/or received power.
A certain well-known power transmitting device senses an approach of a portable electronic apparatus having a high-speed large-capacity storage module which functions as a rechargeable power supply, and transmits power to charge the high-speed large-capacity storage module in response to the sensed approach. With this, the power source is rechargeable at a time of, for example, a noncontact authentication processing operation, by approximation to the authentication device. A charging system performs a charging fee process in accordance with an amount of charge.    Patent Document 1: Japanese Laid-open Patent Publication 8-237890    Patent Document 2: Japanese Laid-open Patent Publication 2005-168085    Patent Document 3: Japanese Laid-open Patent Publication 2006-353042